Packers made of an element that swells in oil or water have been in use for some time as evidenced by U.S. Pat. Nos. 7,997,338; 7,562,704; 7,441,596; 7,552,768; 7,681,653; 7,730,940 and 7,597,152. These designs focus on construction techniques for faster deployment, mechanical compression assists to the swelling or enhancing the performance of an inflatable using an internal swelling material to enhance the seal, elimination of leak paths along the mandrel after swelling and running conduits through the swelling sealing element and still having a good seal.
Shape conforming screens that take the shape of open hole and act as screens have been disclosed using shape memory foam that is taken above its transition temperature so that the shape reverts to an original shape which is bigger than the surrounding open hole. This allows the foam to take the borehole shape and act effectively as a subterranean screen. Some examples of this are U.S. Pat. Nos. 7,013,979; 7,318,481 and 7,644,773. The foam used heat from surrounding wellbore fluids to cross its transition temperature and revert to a shape that let it conform to the borehole shape.
One problem with swelling materials is that the swelling rate can be very slow and that effective deployment requires the swelling to complete to a particular degree before subsequent tasks can commence at the subterranean location. What is known is that if there is more heat that the swelling to the desired configuration, so that subsequent operations can commence, can happen sooner rather than later. Since time has an associated cost, it has been an object to accelerate the swelling or reverting to a former shape process, depending on the material involved.
Various techniques have added heat with heaters run in on wireline or embedded in the packer itself and triggered from a surface location, or have used the heat from well fluid at the deployment location, or heat from a reaction to chemicals pumped to the deployment location, or induction heating of shape memory metallic alloys. Some examples are: US Publication 2010/0181080; U.S. Pat. No. 7,703,539; US Publication 2008/0264647; US Publication 2009/0151957; U.S. Pat. Nos. 7,703,539; 7,152,657; US Publication 2009/0159278; U.S. Pat. Nos. 4,515,213; 3,716,101; US Publication 2007/0137826; CN2,078,793 U (steam injection to accelerate swelling); and US Publication 2009/0223678. Other references have isolated reactants and a catalyst in composite tubulars that have not been polymerized so they are soft so that they can be coiled for deployment and upon deployment expansion of the tubular allows the reaction to take place to make the tubular string rigid. This is illustrated in U.S. Pat. No. 7,104,317.
Bringing together discrete materials downhole for a reaction between them is illustrated in U.S. Pat. No. 5,582,251.
The present invention seeks to accelerate swelling in packers and screens made of swelling material by a variety of techniques. One way is to embed reactants and, if necessary, a catalyst in the swelling material and allow the reaction to take place at the desired location to speed the swelling to conclusion. This generally involves a removal of a barrier between or among the reactants in a variety of ways to get the exothermic reaction going. Various techniques of barrier removal are described. The heat is given off internally to the swelling member where it can have the most direct effect at a lower installed cost.
Another heat addition alternative involves addition of metallic, preferably ferromagnetic particles or electrically conductive resins or polymers in the swelling material. Induction heating is used to generate heat at the particles or resin or polymer to again apply the heat within the element while taking up no space that is of any consequence to affect the ability of the packer to seal when swelling or the screen to exclude particles when the screen is against the borehole wall in an open hole, for example. Optionally the mandrel can be dielectric such as a composite material so that the bulk of the heating is the particles alone. Otherwise the mandrel itself can also be heated and transfer heat to the surrounding element. Induction heating of pipe is known for transfer of heat to surrounding cement as discussed in U.S. Pat. No. 6,926,083 but the rate of heat transfer is very much dependent on a temperature gradient from the pipe into the cement and is less effective than inductively heating the object that needs the heat directly as proposed by the present invention. Also relevant is U.S. Pat. No. 6,285,014 which heats casing with an induction heater lowered into the casing with the idea that the heated casing will transfer heat to the surrounding viscous oil and reduce its viscosity so that it can flow.
Those skilled in the art will better appreciate additional aspects of the invention by a review of the detailed description of the preferred embodiments and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.